The present invention relates generally to the handling of refrigerant, and more particularly relates to apparatus and methods for recovering refrigerant from air conditioning and refrigeration systems for recycling purposes.
Conventional refrigerant recovery systems used to remove refrigerant from air conditioning or refrigeration systems for recycling purposes typically comprise a recovery machine having an inlet port and an outlet port. Operatively disposed between these ports are an accumulator having an inlet connected to the machine inlet port; a condenser having an outlet connected to the machine outlet port; and a compressor having an inlet communicated with the accumulator outlet and an outlet communicated with the inlet of the condenser.
To use the refrigerant recovery machine, its inlet port is connected to an outlet fitting on the air conditioning or refrigeration circuit from which refrigerant is to be recovered, and the machine outlet is connected to the vapor port of a refrigerant receiving and storage tank. Subsequent operation of the machine compressor draws gaseous and liquid refrigerant from the refrigerant circuit and forces it through the condenser and into the storage tank connected to the machine outlet port. When the refrigerant circuit is emptied, the storage tank may be disconnected to permit its received refrigerant to be recycled, or simply left in place to receive another batch of withdrawn refrigerant, depending on the storage tank capacity.
A disadvantage of this conventional single tank recovery system is that the recovery rate of refrigerant forced by the machine compressor into the single tank connected to its outlet port is very slow. For example, a typical recovery rate for this type of machine, when provided with a 0.25 HP compressor, is on the order of 0.33 to 0.5 pounds of refrigerant per minute. Thus, for example, the recovery of a 10 pound charge of refrigerant from an air conditioning circuit normally takes about 20 to 30 minutes, with correspondingly longer time periods for larger charges of refrigerant being withdrawn. Of course, it is possible to increase the recovery rate simply by increasing the size of the compressor. However, this would require that the other components of the recovery machine be correspondingly upsized, thereby undesirably increasing the size, weight and cost of the machine.
From the foregoing it can readily be seen that it would be highly desirable to provide a refrigerant recovery system, preferably utilizing a conventional refrigerant machine of the general type described above, which would significantly increase the refrigerant recovery rate of the machine without increasing the size of its operating components. It is accordingly an object of the present invention to provide such a system and associated refrigerant recovery methods.